Motion Of Carriers Research Articles

Investigation of Sr-substituted Ba1-xSrx(Zn1/3Nb2/3)O3 complex perovskites: structural, electrical and electrochemical properties

Herein we report the structural, dielectric and electrochemical properties of Ba1-xSrx(Zn1/3Nb2/3)O3 (BSZN, 0 ≤ x ≤1) solid solution synthesised by solid-state reaction. A complete substitutional solid solution was obtained, wherein the BSZN cubic perovskites of the space group of Pmm were obtained at x ≤ 0.6 while the pseudo-cubic phases were discernible at x > 0.6. The nano-sized crystallites, as determined by both Scherrer and Williamson-Hall analyses, supported the claim of large polyhedral grains of 0.1 to 0.3 μm by FE-SEM. Both ε′ and tan δ were found to vary consistently with increasing dopant concentration, except for an anomalous observation for the composition, x = 0.6 with the lowest tan δ of 0.0783 and the highest ε′ of 27.5. Such phenomenon could be attributed to the combined effects of larger grain size, higher relative density and stronger polarisation per molar volume. The impedance analysis revealed that these BSZN perovskites were of the negative temperature coefficient of resistance (NTCR) type. The combined plots of imaginary modulus (M″) and impedance (Z″) against frequency showed the short-range movement of localised charge carriers, suggesting a non-Debye-type relaxation process.

Comparison of ZnO Nanoparticles Prepared by Spray Pyrolysis and Consecutive Method for UV-Driven Photocatalytic Degradation of Methylene Blue

ZnO is a semiconductor material that is widely used for many applications in industries such as solar cells, dye-sensitized solar cells, food packaging, photocatalytic, anti-microbial, light-emitting diode devices, and gas sensors. In this study, ZnO nanoparticles (NPs) have been successfully synthesized using two methods, namely spray pyrolysis and a consecutive method. The consecutive method is a combination of sol-gel and spray drying methods. The objective of this study is to investigate the photocatalytic performance of ZnO fabricated using those methods. Both methods used the same precursor, zinc acetate dehydrate as a source of zinc, but with different solvents and additives. Based on the X-ray diffraction pattern, the ZnO NPs synthesized using spray pyrolysis and a consecutive method exhibited similar polycrystalline hexagonal wurtzite structures. The large crystal sizes of ZnO NPs were obtained using a consecutive method, sol-gel followed by spray drying, in comparison with those from the ZnO spray pyrolysis. In contrast, the particle size of ZnO prepared by the consecutive method was in a smaller range. The SEM analysis implied that the ZnO structures had surface defects. In the UV-driven photocatalytic degradation of methylene blue, ZnO produced by the consecutive method exhibited slightly higher degradation performance than ZnO spray pyrolysis. This performance was attributed to the larger crystal size of ZnO NPs, which provided a longer carrier movement at semiconductor surfaces and reduced electron-hole recombination. Additionally, ZnO NPs produced using the consecutive method underwent agglomeration that leads to a smaller contact surface with methylene blue, obstructing the degradation process.

Stimuli-Triggered Diffusion Dynamics in Single-Junction Electrode for Enhanced Supercapacitor Performance: Insights into the Carrier Relaxation and Charge Transfer Kinetics.

Study of external triggers add new chemistry to energy storage research by virtue of controlling diffusion and charge transfer dynamics. Herein, we have chosen a model system, Ag2S-BiVO4 (Ag2S-BVO), for examining the diffusion dynamics upon light illumination using electrochemical and carrier relaxation studies. Favorable band alignments in the single-junction electrode lead to optimized carrier movement across the interfaces, developing a partial positive charge on the electrode, thereby enhancing the mass-transport of electrolyte ions toward the active electrode for efficient charge storage. Synergistic coupling across the heterojunction provides a high areal capacity of 338 mF cm-2 at 0.5 mA cm-2 under light illumination by facilitating the dominant diffusion characteristics within system. In addition, the Ag2S-BVO-based asymmetric supercapacitor exhibits an areal energy density of 32 mWh cm-2 @ 700 mW cm-2 under illumination. This study provides a strategy to tune the capacitive and diffusion contributions for high-performance light-sensitive supercapacitor devices.

Degradation performance of three-dimensional flower-like Cu2O/BiOBr composites in tetracycline degradation

A Z-scheme-structured Cu2O/BiOBr photocatalyst was synthesized by depositing Cu2O cubes onto flower-like BiOBr microspheres and used to degrade tetracycline(TC). The rate of TC degradation by the photocatalyst was 85 % due to its distinctive physical and chemical features. Its exceptional photocatalytic performance could be attributed to its flower-like shape, which enhanced the scattering and refraction efficiency of light and facilitated the separation and movement of carriers. Furthermore, Cu2O/BiOBr exhibited a broad range of light absorption and possessed exceptional photocatalytic characteristics. This paper discussed the photocatalytic mechanism of the Z-scheme Cu2O/BiOBr photocatalyst.

Achieving 11.23 % efficiency in CZTSSe solar cells via defect control and interface contact optimization

The high open-circuit voltage deficit (VOC, def) caused by structural imperfections in the absorber layer and charge loss during carrier transport is a critical barrier affecting the performance of Cu2ZnSn(S,Se)4 (CZTSSe) devices. In this work, Ag was added to the DMF-based Cu+-Sn4+ system, which significantly improved the crystal morphology and electrical properties of the absorber layer. Additionally, optimizing the selenization process not only reduced surface roughness and eliminated voids at the bottom of the absorber layer but also resulted in the formation of a MoSe2 back interface layer with a more suitable thickness. These measures collectively enhanced the overall quality of the absorber layer, reducing the formation of deep-level defect clusters and effectively boosting carrier transport efficiency. Consequently, the concentration of bulk and interfacial defects decreased, and the impact of potential barriers on carrier movement was minimized. With these comprehensive improvements, the power conversion efficiency of CZTSSe solar cells increased from 8.48 % to 11.23 %. Our research demonstrates that optimizing the structure of the absorber layer can effectively enhance the performance of CZTSSe solar cells, providing valuable insights for the fabrication of high-efficiency devices in the future.

Optoelectronic and photoacoustic waves in rotating excited semiconductor subjected to thermal shock

In this study, the impact of rotation on the transmission of optical acoustic waves, arising from the movement of the optical carrier within an elastic thermal environment, is examined through theoretical analysis. The theoretical framework incorporates the interaction between acoustic waves and thermomechanics to formulate governing equations specific to a semiconductor medium. The fundamental equations of the physical model, influenced by photothermal and thermoelastic principles, are deduced mathematically while considering the presence of rotation. The model studied the medium under a thermal shock wave from thermal stress resulting from light-induced temperature elevation that is not fixed but decaying over time. The mathematical model is solvable using the normal mode method. The model’s numerical solutions provide access to all physical fields within the physical domain, encompassing displacement, temperature, acoustic pressure, mechanical stress, and carrier density diffusion. Utilizing the harmonic wave method, a two-dimensional graphical representation of the rotation parameter with and without the influence of the decay parameter is obtained. The theoretical analysis involves comparison, analysis, and discussion of the effects of these parameters investigated.

Methods in fluctuation (noise) spectroscopy and continuous analysis for high-throughput measurements

Abstract Fluctuation (noise) spectroscopy is widely used to investigate the low-frequency dynamics of charge carriers in condensed-matter systems, aiming to (i) improve the performance of micro- and nanoscale electronic devices and sensors, and (ii) use ‘noise as a signal’ in order to fundamentally investigate the microscopic motion and transitions of charge carriers coupled to the low-lying excitations in solids. Here, we focus on measurements of the ubiquitous 1 / f -type fluctuations, often composed by a superposition of (independent or correlated) two-level systems each giving rise to a Lorentzian spectrum, denoted random telegraph noise in the time domain. We briefly review the basic concepts of noise and fluctuations and give a comprehensive overview of state-of-the-art measuring techniques, using both commercially available signal analyzers and custom software in order to perform the spectral analysis of the recorded time signals, and critically evaluate their advantages and drawbacks. We describe how to use fast data acquisition devices in a cross-correlation setup providing additional quantitative information on the magnitude of uncorrelated instrument noise, and demonstrate the mathematical intricacies of extracting the noise spectra. We introduce a new method for high-throughput measurements by automated spectral analysis based on the concept of Continuous Analysis. We demonstrate the potential of this technique, working towards a FAIR data workflow, by measurements of magnetic flux noise within the hysteresis loop of ferromagnetic nanostructures.

Strong Robust LIO System Based on Event Camera Assistance

Abstract. At present, the LiDAR system can achieve high precision and is extensively used for indoor and outdoor mobile positioning and mapping. However, LiDAR systems still face issues in cluttered environments where strong features are absent, leading to a degradation of the LiDAR-based solution. When the carrier movement involves high-speed or prolonged exposure to the mirror wall, it can cause severe degradation issues or even positioning failures in the laser slam system. Event cameras are vision sensors inspired by biology that exhibit strong robustness in high dynamic and low texture environments, potentially leading to better performance in such environments. However, some issues with event cameras remain unresolved. In this paper, a multi-source fusion method based on EVIO, LIO and IMU trajectory layer post-processing method is proposed, which will fully consider the robustness of event camera in high dynamic environment and the high precision advantage of Lidar in conventional environment, and use an algorithm based on normalized uncertainty. The elastic multi-source fusion of event camera and LiDAR is realized and tested in realde environment. Experimental results show that the proposed algorithm can effectively improve the accuracy of event camera and LiDAR. Compared to the current more advanced algorithms, the proposed algorithm effectively addresses the problem of LIO in degraded environments. Additionally, it mitigates the scale inaccuracy and divergence of the EVIO trajectory to some extent. Compared to LIO, the algorithm can reduce the maximum position error by approximately 30% and increase the overall position accuracy by 32%. Additionally, it can significantly constrain the divergence of errors in the Y direction, improving its accuracy by about 75% and 65% compared to the LIO and EVIO algorithms, respectively.

Epitaxial Growth of a Three-Dimensional Hollow and Chestnut Shell Photothermal p-n Junction Photoanode.

The p-n junction, a widely studied semiconductor material structure, offers only limited improvements in photoelectrochemical (PEC) efficiency. Herein, a three-dimensional (3D) p-n junction h-Ta3N5@CoN featuring a stable chestnut shell hollow sphere structure and photothermal effect was synthesized by using an epitaxial growth strategy. The fine fibers within the sphere induce Rayleigh scattering, which scatters unabsorbed light, thereby enabling secondary absorption and enhancing light utilization. The quantum confinement effects generated by CoN fine fibers, which are sized in a few nanometers, inhibit the recombination of electron-hole pairs. Moreover, the lattice matching between Ta3N5 and CoN allows for smoother movement of carriers and nonradiative relaxation phonons along the lattice, thereby enhancing the transport of both carriers and heat. The obtained h-Ta3N5@CoN/FTO p-n junction photoanode, under near-infrared (NIR) auxiliary irradiation, demonstrates a photocurrent of 8.71 mA cm-2 at 1.23 VRHE. Moreover, the h-Ta3N5@CoN+NIR/FTO photoanode can sustain operation for 168 h, which, to my knowledge, surpasses the operational durations of all other Ta3N5-based photoanodes. This study synthesizes three-dimensional hollow chestnut shell photothermal p-n heterojunctions through an epitaxial growth strategy, endowing the material with a more efficient carrier separation and photothermal transfer efficiency.

Structural and morphological studies of g-C3N4-functionalized MWCNTs nanocomposite for sunlight-responsive photocatalytic activity

Photocatalytic degradation of organic contaminants has been proven to be one of the greatest economical and efficient techniques to address environmental pollution problems. Multi-walled carbon nanotubes (MWCNTs)/g-C3N4 (GCN) nanocomposites (NCs) were synthesized by a hydrothermal process aided by ultrasound to produce active photocatalysts. The effective synthesis of GCN, MWCNTs, and MWCNTs/GCN NCs was confirmed by X-ray diffraction (XRD) patterns. The fabrication of GCN nanosheets (NSs), the nanotubular structure of MWCNTs, and a network of neuron-like structures for MWCNTs/GCN NCs were all revealed by structural and morphological characterization. The elemental mapping of NCs containing the suitable quantity of MWCNTs revealed a uniform distribution of the sample's component elements. When the optical properties of the fabricated nanomaterials were examined by employing UV–visible spectroscopy, the results revealed a blue shift (a shift of maximum absorption to the UV region), which suggests that the addition of MWCNTs increased the band-gap energy. The behaviour of e––h+ pair recombination was revealed by measuring the charge carrier movement and trapping efficiency using photoluminescence (PL) spectroscopy. Crystal violet (CV) dye was photocatalytically degraded using prepared NCs in the presence of sunlight, and the synergistic effects of GCN and MWCNTs were examined. With a degradation efficiency of 99.32 %, MWCNTs/GCN NCs demonstrated the best sunlight-irradiated photocatalytic activity for CV degradation. The degradation of CV was discovered to follow pseudo-first-order kinetics. Throughout five consecutive studies, the NCs demonstrated the highest levels of catalytic efficiency and recyclability, with 5 % reduced degrading activities. The trapping tests showed that the primary reactive species involved in the breakdown of CV were the •O2– and •OH radicals.

Multi-scale structural regulation of negative temperature coefficient effect and electrical conduction mechanism of xSm2O3-(1-x) CaCu3Ti4O12 ceramics

In this work, a series of xSm2O3-(1-x) CaCu3Ti4O12 (xSm2O3-(1-x)CCTO, x = 0.00-0.05) negative temperature coefficient (NTC) ceramics were prepared by a solid-state method. The influence of Sm2O3 content on electrical properties was examined using microstructural, band gap, morphological, Direct Current (DC) resistivity, and impedance spectroscopy analysis. The increase in Sm2O3 content resulted in a gradual decrease of the resistivities (ρ25), thermal constants (B25/75), activation energies for electrical conduction (Ea) and activation energies of the relaxation process (Erelax) from 1.16×107 Ω•cm, 6387 K, 0.5456 eV and 0.5592 eV to 3.43×105 Ω•cm, 4149 K, 0.4088 eV and 0.4115 eV respectively. First-principles calculations revealed a reduction in the band gap by adding Sm2O3, partially explaining the decrease in electrical resistivity. In-situ XPS analysis elucidated a relationship between conduction mechanism of Sm2O3-doped CCTO ceramics and electron hopping. Impedance analyses showed that both grains and grain boundaries contributed to the NTC effect of ceramics. The electrical inhomogeneity arose from grains and grain boundaries, while local relaxation was due to the short-range motion of charge carriers.

A Functional "Key" Amplified Piezoelectric Effect Modulates ROS Storm with an Open Source for Multimodal Synergistic Cancer Therapy.

Chemodynamic therapy (CDT) is a non-invasive strategy for generating reactive oxygen species (ROS) and is promising for cancer treatment. However, increasing ROS in tumor therapy remains challenging. Therefore, exogenous excitation and inhibition of electron-hole pair recombination are attractive for modulating ROS storms in tumors. Herein, a Ce-doped BiFeO3 (CBFO) piezoelectric sonosensitizer to modulate ROS generation and realize a synergistic mechanism of CDT/sonodynamic therapy and piezodynamic therapy (PzDT) is proposed. The mixed Fe2+ and Ce3+ can implement a circular Fenton/Fenton-like reaction in the tumor microenvironment. Abundant ·OH can be generated by ultrasound (US) stimulation to enhance CDT efficacy. As a typical piezoelectric sonosensitizer, CBFO can produce O2 - owing to the enhanced polarization by the US, resulting in the motion of charge carriers. In addition, CBFO can produce a piezoresponse irradiated upon US, which accelerates the migration rate of electrons/holes in opposite directions and results in energy band bending, further achieving toxic ROS production and realizing PzDT. Density functional theory calculations confirmed that Ce doping shortens the diffusion of electrons and improves the conductivity and catalytic activity of CBFO. This distinct US-enhanced strategy emphasizes the effects of doping engineering and piezoelectric-optimized therapy and shows great potential for the treatment of malignant tumors.

Sustainable Wastewater Treatment with Bi2MoO6/Cellulose Acetate Photocatalytic Membranes

AbstractA major challenge for modern society is securing quality water for various uses. Membrane water treatment will be crucial for drinking water, desalination, and wastewater reuse. The development of bismuth molybdate (Bi2MoO6) nanoparticles has enabled the production of novel Bi2MoO6‐incorporated cellulose acetate (CA) membrane nanocomposite. The synthesized Bi2MoO6/CA nanocomposites are thoroughly examined for their structural, morphological, and photocatalytic characteristics using X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) with energy dispersive X‐ray spectroscopy (EDX) analysis. The photocatalytic properties are determined by evaluating the degradation of Malachite Green (MG) and Rose Bengal (RB) by the nanocomposite membranes under the illumination of a UV light simulator. Notably, the Bi2MoO6/CA nanocomposite membrane displays exceptional and sustained photocatalytic efficiency (78%) and (84%) in MG and RB dye degradation, respectively. Moreover, the effective loading of the Bi2MoO6 onto the CA membrane enhances electron and hole adsorption while facilitating carrier movement. Furthermore, the stability exhibited by the Bi2MoO6/CA nanocomposite photocatalysts remains impressive even after multiple cycles, demonstrating their durability. This research introduces a cutting‐edge semiconductor‐based hybrid nanocomposite material that proves highly efficient in the photocatalytic degradation of organic dyes, showcasing promising advancements in environmental remediation strategies.

Structural, optical, and morphological properties of PVC-BaTiO3 nanocomposite films

This work aims to fabricate barium titanate (BaTiO3) nanoparticles and study the effect of adding different contents of BaTiO3 nanoparticles on the structural, optical, and electrical properties of PVC polymer matrices. The PVC/BaTiO3 nanocomposite films were characterized by X-ray diffraction, FT-IR spectroscopy, and SEM. In addition, dielectric properties were studied within the frequency range of 0.1 KHz–6 MHZ. The XRD analysis reveals an amorphous nature of pure PVC with two characteristic peaks at 2θ = 17.09° and 2θ = 23.25°, and it reveals that BaTiO3 has sharp and narrow peaks. In PVC/BaTiO3 nanocomposite films, all XRD peaks of BaTiO3 appeared in all the samples with an increase in the average particle size from ∼46 nm to 55 nm. There is no shift of IR position in PVC bands, but the decreased intensity of some bands suggests complexation between PVC and BaTiO3. The UV–visible absorption spectrum of pure PVC has a band at λ = 278 nm. This band was shifted to 252 nm after adding BaTiO3 content. UV–visible transmission spectra demonstrate a decrease in the transmittance as an increase of BaTiO3 content from 89.23 % for pure PVC to 5.23 % for 0.1 wt% of BaTiO3. The values of the optical bandgap decrease with increasing BaTiO3 contents due to defect formation in PVC matrices. The optical parameters of the prepared nanocomposite films were also enhanced. The AC conductivity shows an increase with both frequency and BaTiO3 concentration, leading to enhanced movement of charge carriers and relaxation of interface polarization.

Boosted Electrochemical Activity with SnO2 Nanostructures Anchored on α-Fe2O3 for Improved Charge Transfer and Current Density

This study presents a straightforward and cost-effective method to enhance the photoelectrochemical (PEC) water-splitting performance of α-Fe2O3 (F), SnO2 (S), and α-Fe2O3 decorated with SnO2 quantum dots (FS) photoanodes in a NaOH electrolyte. The FS electrode demonstrated a notable improvement in PEC efficiency within the electrolyte. In particular, the generated charges of the FS anode in the NaOH electrolyte reached approximately 12.01 mA cm−2 under illumination, indicating that the developed heterostructures effectively enhanced kinetics, leading to improved separation of induced carrier pairs. This active carrier-pair separation mechanism contributed considerably to the increased PEC activity in the 0.1 M NaOH electrolyte. The reduction in the bandgap of FS increased its absorption capability in visible light, which further enhanced the current density. Furthermore, the reduction in electrolyte resistance (9.71 Ω), internal resistance (20.19 Ω), charge transfer resistance (3.21 kΩ), Tafel slope (45.5 mV dec-1), limiting current density (−2.09 mA cm−2), and exchange current density (−3.68 mA cm−2) under illumination at the interface enhanced the charge density of FS. Further, a strong interaction among photoanode nanostructures significantly enhances PEC activity by improving efficient charge separation and transport, reducing recombination rates, and enabling quicker movement of charge carriers to the electrode/electrolyte interface. Thus, this study provides an effective approach to increasing the PEC activity of heterostructures.

An Advanced Control Method for Aircraft Carrier Landing of UAV Based on CAPF–NMPC

This paper investigates a carrier landing controller for unmanned aerial vehicles (UAVs), and a nonlinear model predictive control (NMPC) approach is proposed considering a precise motion control required under dynamic landing platform and environment disturbances. The NMPC controller adopts constraint aware particle filtering (CAPF) to predict deck positions for disturbance compensation and to solve the nonlinear optimization problem, based on a model establishment of carrier motion and wind field. CAPF leverages Monte Carlo sampling to optimally estimate control variables for improved optimization, while utilizing constraint barrier functions to keep particles within a feasible domain. The controller considers constraints such as fuel optimization, control saturation, and flight safety to achieve trajectory control. The advanced control method enhances the solution, estimating optimal control sequences of UAV and forecasting deck positions within a moving visual field, with effective trajectory tracing and higher control accuracy than traditional methods, while significantly reducing single-step computation time. The simulation is carried out using UAV “Silver Fox”, considering several scenarios of different wind scales compared with traditional CAPF–NMPC and the nlmpc method. The results show that the proposed NMPC approach can effectively reduce control chattering, with a landing error in rough marine environments of around 0.08 m, and demonstrate improvements in trajectory tracking capability, constraint performance and computational efficiency.

Enhancing thermoelectric performance with perpendicular anisotropic magnetic domain arrays

In recent years, the incorporation of magnetic nanoparticles into thermoelectric materials has been introduced to enhance their performance. However, understanding the impact of dispersed magnetic substances in the matrix on thermoelectric properties, considering different domain directions, is crucial for performance improvement. In this study, we have designed and fabricated high-quality epitaxial single crystal thin films consisting of FePt arrays with varying magnetic domain directions embedded in an Sb2Te3 matrix. Our findings reveal that the electrical transport behavior of the films responds differently to magnetic materials with distinct domain directions, especially in the case of discontinuous arrays. The FePt array oriented perpendicular to the carrier flow direction effectively regulates the direction of carrier movement and local low-energy carriers, functioning as an "energy supplier" to enhance material performance. Simultaneously, the quantum dots formed between the Sb2Te3 and the metal film play the role of carrier channels, further regulating the carrier concentration. Therefore, the perpendicular magnetic anisotropy array synergistically modulates the electrical transport behavior through carriers, resulting in a significant improvement in the thermoelectric power factor. By increasing the S value at the measurement temperature, we achieved a maximum power factor (PFmax) of 3.35 mWm-1K-2 and an average power factor (PFave) of 3.14 mWm-1K-2.

SnO wrap on SnS reinforced thermoelectric properties of CF/EG cement matrix composites

In this study, SnO wrap on SnS was prepared and incorporated into carbon fiber/expanded graphite (CF/EG) cementitious composites by the coating process. The effects of different SnO wrap on SnS coating ratios and contents on the microstructures of CF/EG cementitious composites were investigated and discussed, and the thermoelectric properties of SnO wrap on SnS CF/EG cementitious composites were systematically investigated in the temperature range of 35–70 °C. The results show that the coating ratio and content of SnO wrap on SnS have a significant effect on the thermoelectric properties of CF/EG cementitious composites. It is noteworthy that when the SnO wrap on SnS is 2:1, the thermoelectric properties of its cementitious composites are greatly improved. For example, when it is added at 1.0 wt%, the conductivity is 2.27 S/cm, the Seebeck coefficient is 41.90 µV/°C and the power factor is 0.38 µW·m−1K−2. The addition of SnO wrap on SnS to CF/EG cementitious materials generates a large number of interfaces, and the presence of high-density interfaces hinders the motion of carriers, which leads to the scattering of carriers at the interfaces and enhances the Seebeck effect in cementitious composites. Therefore, SnO wrap on SnS has great potential for thermoelectric applications.

TCAD simulation of germanium-based heterostructure solar cell employing molybdenum oxide as a hole-selective layer

Molybdenum Oxide (MoO x ) has been used as a hole-extraction film for photovoltaic (PV) applications; however, its interaction with Germanium (Ge)-based solar cells is less understood. For the first time, this paper aims to physically model the Ge solar cell that incorporates MoO x for hole transportation at the front side of the PV device facing the sunlight. However, the charge transportation process within the PV device is influenced by several design parameters that need optimization. A higher work function of MoO x increases the barrier height against minority carriers of electrons which is beneficial for extricating holes at the front interface of MoO x /Ge. A progressive reduction in the recombination of charge carriers has been observed by including a passivation layer of amorphous silicon (i-a-Si:H). Similarly, inserting a passivation and back surface field (BSF) stack of i-a-Si:H strengthens the electric field and likewise reduces the recombination at the rear side of the device. An enhanced doping concentration of BSF assists in the favorable alignment of energy bands for improved charge transportation within the solar cell as the rear passivation maintains the field strength for accelerated movement of charge carriers. However, optimizing the thickness of the front-passivation film is challenging due to the parasitic absorption of light at larger thicknesses. A comparative study with the reference device revealed that the proposed device exhibited a step-increase in the conversion efficiency (η) from 4.23% to 13.10%, with a higher J sc of 46.4 mA cm−2, V oc of 383 mV, and FF of 74%. The proposed study is anticipated to meet the research gap in the physical device modelling of Ge-based solar cells employing high work function MoO x as a carrier-selective layer that could be conducive to the development of highly efficient multijunction solar cells.

Enhancing the performance of the BaTiO3 electrolyte via A-site-deficiency engineering for low-temperature ceramic fuel cells (LT-CFCs)

The development of low-temperature solid oxide fuel cells (LT-SOFCs) is gaining abundant interest in semiconductor ionic materials (electrodes and electrolytes). Following this concept, an A-site deficiency technique is employed to unilaterally change BaTiO3 to regulate ionic conduction, further improving the electrolyte's performance. The electrolytes, namely BaTiO3, Ba0·95TiO3, and Ba0·90TiO3, have carefully been constructed and studied utilizing solid-state ball milling. The A-site deficiency in BaTiO3 resulted to improve the ionic conductivity and minimize activation energy. This can be attributed to the higher number of oxygen vacancies on the surface and at the interfaces. The enhanced morphology, direct visualization of lattice structures, and the existence of oxygen vacancies caused by A-site deficiency have been studied in detail. Out of all the prepared electrolytes, Ba0·90TiO3 shows an enhanced fuel cell performance of 625 mW/cm2. In comparison, the Ba0·95TiO3 achieved a reasonable fuel cell performance of 573 mW/cm2, and BaTiO3 achieved 548.40 mW/cm2 at a low temperature of 550 °C. Compensating for the lack of A-site ions is a successful approach to improve ion transportation in fuel cells without creating any leakage of electric current. This is achieved by modifying the arrangement of energy bands that control the movement of charge carriers. The results of this work demonstrate that A-site-deficiency engineering can be used to improve the electrolyte performance of LT-SOFCs, making it a promising method for advancing fuel cell technologies in the future.